Someone pls i'm not sure how to do this can someone explain pls

Step-by-step explanation:

Volume = 2 ( x + 3) ( x-1 )(x  + 3 ) + (2x) (x + 3) ( x + 3  - 2x )

= 2 ( x + 3) ( x-1 )(x  + 3 ) + (2x) (x + 3) ( 3  - x )

= 2 (x - 1 ) (x² - 9) +  2x *  (9 - x²)

= 2 (x - 1 ) (x² - 9) -  2x *    ( x² - 9)

=  (x² - 9)  ( 2x - 2  - 2x )

=  (x² - 9) (-2)

= -2x²  + 18

well what did you do it matters what you did : )

step-by-step explanation: